Impact crushers of the impeller type typically utilize a rotor having several axially extending impeller bars disposed in recesses about its periphery. The impeller bars strike the rock entering the crusher and hurl it against one or more sets of breaker bars in the process of reducing the rock to size. From time to time the impeller bars, since they are abraded by the rock, must be adjusted to compensate for wear and then finally replaced which in turn requires that they be removably attached to the rotor. At the same time the attachment must be mechanically secure and rigid enough for the bars to withstand the rapid and repeated blows with which they strike the rock.
The prior art abounds with schemes for removably affixing impeller bars to their rotors. The most prevalent, it seems, employ wedges of various configurations and functions, whether the rotors themselves are of the "solid" cast type or of the "open" type consisting of several axially spaced discs. Generally speaking, the wedges in these instances act in one of two ways: either radially of or axially of the rotor. Examples of the first kind are found in U.S. Pat. Nos. 2,747,803; 3,784,117; 3,979,078; 4,573,643; and 4,679,740. Examples of the second kind are shown in U.S. Pat. Nos. 2,258,075; 3,202,368; 3,455,517; 3,874,603; and 4,373,678. But in varying degrees all of the foregoing suffer from one or more of the following: complexity, weight, poor accessibility for inspection, adjustment or replacement, high manufacturing costs, and "liming" which increases the difficulty of adjustment or replacement. So the chief object of the present invention is a wedging arrangement for the impeller bars of an "open" type rotor which reduces or eliminates the impediments and detractions typical of the prior art. Another object of the invention is a simple but effective manner of manipulating the impeller bars when installing them initially and for repositioning them later to compensate for wear.